* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 600px;
    margin: 0 auto;
    background: white;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    overflow: hidden;
}

header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 30px;
    text-align: center;
}

h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
    font-weight: 700;
}

.subtitle {
    opacity: 0.9;
    font-size: 1.1em;
}

.input-section {
    display: flex;
    padding: 20px;
    gap: 10px;
    background: #f8f9fa;
}

#taskInput {
    flex: 1;
    padding: 15px;
    border: 2px solid #e9ecef;
    border-radius: 10px;
    font-size: 16px;
    transition: border-color 0.3s;
}

#taskInput:focus {
    outline: none;
    border-color: #667eea;
}

#addBtn {
    padding: 15px 25px;
    background: #667eea;
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    font-size: 16px;
    transition: background-color 0.3s;
}

#addBtn:hover {
    background: #5a6fd8;
}

.stats {
    display: flex;
    justify-content: space-around;
    padding: 15px 20px;
    background: #f8f9fa;
    border-bottom: 1px solid #e9ecef;
}

.stats span {
    font-size: 14px;
    color: #6c757d;
}

.stats strong {
    color: #667eea;
    font-size: 16px;
}

.filter-section {
    display: flex;
    padding: 15px 20px;
    gap: 10px;
    background: white;
    border-bottom: 1px solid #e9ecef;
}

.filter-btn {
    padding: 8px 16px;
    border: 1px solid #e9ecef;
    background: white;
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.3s;
    font-size: 14px;
}

.filter-btn.active {
    background: #667eea;
    color: white;
    border-color: #667eea;
}

.task-list {
    list-style: none;
    padding: 0;
}

.task-item {
    display: flex;
    align-items: center;
    padding: 20px;
    border-bottom: 1px solid #e9ecef;
    transition: background-color 0.3s;
}

.task-item:hover {
    background: #f8f9fa;
}

.task-item.completed {
    opacity: 0.7;
}

.task-item.completed .task-text {
    text-decoration: line-through;
    color: #6c757d;
}

.task-checkbox {
    margin-right: 15px;
    width: 20px;
    height: 20px;
    cursor: pointer;
}

.task-text {
    flex: 1;
    font-size: 16px;
    color: #333;
    word-break: break-word;
}

.task-actions {
    display: flex;
    gap: 10px;
}

.edit-btn, .delete-btn {
    padding: 8px 12px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 14px;
    transition: background-color 0.3s;
}

.edit-btn {
    background: #ffc107;
    color: #212529;
}

.edit-btn:hover {
    background: #e0a800;
}

.delete-btn {
    background: #dc3545;
    color: white;
}

.delete-btn:hover {
    background: #c82333;
}

.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: #6c757d;
}

.empty-state i {
    font-size: 4em;
    margin-bottom: 20px;
    opacity: 0.5;
}

.empty-state p {
    font-size: 18px;
}

.editing {
    flex: 1;
    padding: 5px;
